Hermetically sealed socket with freely floating contacts



NOV 3, 1953 c. w. KLOSTERMANN ET AL 2,658,183

HERMETICALLY SEALED SOCKET WITH FREELY FLOATING CONTACTS Filed March 13 1950 INVENTORS: lMZJ/ma/m Patented Novs 3, 1953 HERMETICALLY SEALED SOCKET WITH FREELY FLOATING CONTACTS Curt W. Klostermann, Chicago,

and Charles J.

Adams, Park Ridge, Ill., assignors to American Phenolic Corporation, Chicago, Ill., a corporation of Illinois Application March 13, 1950, Serial No. 149,292

2 Claims. 1

The present invention relates to electronic tube sockets and -similar electrical connectors, and has particular reference to an electronic tube socket suited for use with hermetically sealed equipment.

It is well known that certain types of electronic equipment, particularly milit-ary equipment intended for operation in areas of extremely adverse climatic conditions, should be hermetically sealed in order to exclude air from the housing in which the equipment is mounted, and, consequently, to prevent condensation of moisture and the formation of fungus growths which would otherwise soon interfere with the proper operation of the equipment. It is nevertheless necessary, however, that the electronic tubes themselves be outside of the sealed housing, since these tubes must be replaced from time to time, as it is important to be able to replace the tubes without destroying the seal around the rest of the equipment. This poses a diilicult problem of electrical design, since it is entirely impractical to .attempt to seal the conventional type of electronic tube socket, and it has been found equally impractical to utilizesatisfactoryhermetic sealing devices in such a manner as to establish electrical connections with a conventional socket outside ci the sealed chassis of the equipment.

One of the most satisfactory forms of hermetically sealed conductors thus far developed comprises a short metallic pin which extends through a small glass bead fused in a fianged aperture or a sheet metal wall. The bead is bonded both to the wall and to the pin, so that the bead is the sole mechanical support of the pin, which serves as an electrical conductor entering through the wall. These fused glass seals have shown themselves to be highly eflicient from an electrical standpoint, but have the recognized shortcoming that they are extremely fragile mechanically and are easily subject to fracture if subjected to any appreciable force, particularly to any force `.acting laterally with respect to the individual pins. For this reason, they have hereto-fore been regarded as unsuited to utilization as contact members in electronic tube sockets, since these are often subjected to considerable vibration and to severe impacts. In addition to this, however, and probably more important, is the fact that it is a recognized essential that some lateral play and movement of the socket contacts must be possible in order to compensate for tolerance variations in the spacings of the tube pins. It has accordingly been regarded as utterly impractical to attempt to employ hermetic seals 2 of the glass bead type to establish connection from within Aa sealed chassis to a tube socket carried in the chassis Wall.

It is the primary object of the present invention to provide an electronic tube socket for hermetically sealed equipment, wherein a perfect hermetic seal is maintained, yet the socket is nevertheless capable oi accommodating tubes having their pins imperfectly spaced, and to establish proper electrical connection with tubes having oversize pins, which also impose abnormal strains on the socket contacts. This is done, according to the present teaching, by employing a socket body and free floating contacts of novel design, which coact to permit considerable lateral movement of the pin contacts within the socket, as well as to accommodate oversized or undersized pins, yet to absorb lateral stresses set up by imperfect pin spacing and to adequately resist the abnormal inward and outward thrusts exerted by oversize pins, so that such tubes may be inserted in or removed from the socket without damaging the fragile sealing devices. To this end the present invention contemplates the use of a socket having an airtight metal sealing wall employing a plurality of glass bead seals having center pin-s to establish electrical connection through the Wall, together with `an insulating socket body into which the pins of the seals extend. The socket body is provided with a plurality of independent socket contacts, each of which is mounted in what may be termed a freely floating manner, so that it is conined, yet free to shift a limited amount in any direction. These socket contacts have oppositely disposed friction sleeves to engage the pins of the seals at one end and the tube pins at the other, so that the individual contacts may freely position themselves according to the pin spacing of the tube inserted into the socket, in such a manner hat they will establish an efficient electrical connection between the pins oi a tube inserted in the socket and the pins oi the hermetic seals extending through the sealing wall, yet will impose no physical strains on the seals.

The present preferred embodiment of the invention is illustrated in the drawings of this specication, wherein:

Figure l is a plan view of a socket vconstructed in accordance with these teachings; and

Figure 2 is an enlarged sectional view taken substantially on the plane of the line 2-2 of Figure 1. f

The socket is illustrated as attached to a thin sheet metal wall l0, which represents the exterior essaies is soldered in an aperture I in the wall I0, so

that the shell acts as a sealing member which coacts with the wall to form an airtight partition providing an effective hermetic seal for the equipment within the chassis.

The electrical connections from ithe inside of Y the chassis to the socket are establishedthrough, one or more conductors I6 extending through apertures in the lower plate I3 of the socket. As illustrated, these conductors I6 consist of slender metal pins provided with terminal eyelets I1 at their outer end and have straight shank portionsl I8 projectingupwardly into the'socket shell I2. These conducting pins are bonded-to glass insulating beads ZI, which are in turn mounted and sealed in the contact apertures 122 of the socket. As. shown, these beads are fused directly to the downwardly extendingl flanges 23 of these apertures.

The socket body is of insulatingmaterial and, as illustrated, consists Yof a lowerv dielectric insert 25 molded to t in the bottom of themetallic shell I2, andan upper dielectric insert 26 shaped to be received in the shell above the inn sert 25, so that both ofthe inserts may be permanently held in assembled relationship with the shell by a plurality of crimps 2l wherein the metal of the shell wall I2 is deformed into re-A cesses 28 molded on the exterior. surface of the upper dielectric insert 28. The V,lower insert 2 is pierced with an aperture corresponding to the position of each of the conductor pins I6, so that each of thesepins projects upwardly into .an individual aperture of the insert. These apertures are preferably. of sufliciently large diameter.

to give ample clearance around each of the pins, so that the pins stand free-of theinsulating material and are Supported solely bythe glass beads 2I. The openings 3| may include enlarged portions 32 at their lower end to afford adequate clearance around each of the insulating beads, and enlarged portions 33 at their upper ends, to form a part of an enlarged cavity.

The upper dielectric insert 26 has pin apertures 34 corresponding in position to the positions of the pins I6` but slightly offset. therefrom, and each of these pin apertures enters an enlarged gravity 35 which coacts with the enlarged portion 33 of the cavity in the lower insert to receive a metallic lcontact generally designated `by the numeral 36. The cavities 33 and Simay be concentric if desired, but in the form ofthe invention illustrated, their centers,

a the airtight wall .le of the chassis.

this soldering may be done before the inserts 25.

are slightly offset from eachY otherfsothatzalthough the cavities 35 aresomewhat larger than the cavities 33, their side walls may be substantially parallel along one side (see Figure 1)'. To

this end, the upper and lower inserts 25 and 26 are keyed to eachother by a key portion 3l extending into a keyway 3B in the-flange 39, which surrounds a reduced upper end portion 4I of the insert 25. The enlarged portions v33- and 35 ofv each of the insert cavities coact to housea contact 36, `which comprises a double ended, free floating spring sleeve. sleeve includes kan. oversizeulowerftubular sleeve 42 (of diametersubstantially greater than the As illustrated, the spring diameter of the pin shank I8) having a constricted contact point 43 of proper size to receive the upper end of one of the pins I5, and an outwardly flared mouth 44. The sleeve 4'2 is preferably split along one side for its full length, and may be split -on its` opposite -jside as at 45, vso that the inherent resiliency Vof thefmetal from which it is formed will afford a snug frictiont of the contact point 43 on the exterior surface of the pin. By this arrangement an electricalcontact of low resistance is achieved, yet the contact sleeve is ree to slide longitudinally along the pin and may move considerably out of axial alignment with the pin without imposing any appreciable strains thereon. The upper end of the contact 3B comprises an oversize spring sleeve 45 having a constricted contact point 41 and an outwardly flared mouth 43 shaped to receive a contact pin of a vacuum tube inserted in the socket. Such a contact pin is represented in the drawings by the pin 50. A keyedcentral recess 49 is formed in. the insert 26.to. receive the pilot shank of the tube.

The lower sleeve l2 and upper sleeve 45.01 the.. contact are formed of a single integral piece of sheet lmetal shaped to .include a central section yiii which extends between .the two sleeves and,... which has an outwardly extending key-.or tabv52 received in -a keyway 53-on one side of the enlarged portion 35 of the upper cavity.

On. review of the structure illustrated above, it

i4 of the metal socket shell is soldered directly `to and 'it are placedin position, so that .the inserts are not subjected tothe heatoi the soldering operation., This makes it feasible `to employlow temperature-plastic for said inserts if desired.. The side walls I2 and bottom I3.of the socket cup form a continuous metal partition interrupted.

only by the glass seals 2l fused in and bonded to the flanges 23. These seals eiiect a perfect airtight Vbond between the metal of the socket shell aswell as with the .centraliconductord and thereby eilect a seal which is entirely` impervious to air and moisture.

The dielectric inserts 25 and 26. of the socket are of such shape'that theyY need not Contact.y

the pins I6 at any time, with the result. that these pins aresupported solely by the glass beads 2i.V and are thus protected against any. external. lt is to be understood, of course, that.l

stresses. as tubes are inserted into or removedfrom the socket, the frictional engagement between ther tube pins 5e and the upper spring sleeves 45.01?.

the contacts 36 will cause downward thrusts on the contact as thetubes are inserted into the socketaand upward `thrusts thereon whenevera tube is removed. It is to be noted,I however,V that these Vthrusts are not transmitted to the pins I6, since even `when a tube having oversize conA tact pins is inserted in the socket, the abnormal thrustwhich it imposes on the contact serves.n only to move the lower. end of the `contact mouth 44 into abuttingengagement withv the` upwardly. disposed shoulder' 511 at the bottom of the. cavityv 33, so that the thrust is received on this insulat-A ling shoulder rather than onthe pin I6.

The force that can be imposed on the pins i6 is thus limited to the degree of frictionalengagement between the constricted contact Y4.*1rof'the sleeve 42'and the cylindricalsurface'of `theshank I8"- Similarly, any upward thrust de-M of -the pin.

If desired,.

veloped as a result of the removal of a tube from the socket is not exerted on the pins i6, but is absorbed as the upper end of the mouth portion 4'8 of the sleeve 46 comes into engagement with the downwardly disposed shoulder 55 of the upper dielectric insert 26 (Figure 2). The key 52 of each of the socket contacts prevents rotational movement of the contacts within their cavities and thus maintains the sleeves 42 in properly centered relationship with the pins I6 and holds the sleeves 46 properly centered below the pin apertures 34. It is to be remembered, however, that it is one of the primary aims of the present invention to prevent damage to the hermetic seal as a result of inserting or attempting to insert into the socket tubes having bent pins or pins otherwise out of proper spacing or alignment with each other. Such tubes may be received in the socket since the apertures 34 are somewhat larger than the contact pins 50, and while any misaligned pin will cause corresponding lateral movement of the contact sleeve 46 in which it is received, this movement will be primarily at the constricted point of contact 41 between the sleeve and the pin, and will serve to tilt the contact in its socket rather than to move it bodily in a lateral direction. Thus the upper end of the contact may move in any lateral direction without imposing any corresponding strains on the pins I6, due to the fact that the contact between the sleeves and these pins is exerted primarily at the constricted point 43, so that the contact may tilt substantially without tending to move the upper end of the pin.

From the above it is believed apparent that 3 by the present teachings it is entirely feasible to employ hermetic sealing devices consisting of a conducting pin extending through a metallic sealing wall and supported therein solely by a fused glass bead, since a socket constructed according to the present teaching prevents any strains incident to the insertion or removal of the tube being transmitted to the pin in such a manner as to cause damage to the seal. The socket is equally effective in resisting strains caused by impacts on the tubes cr chassis while in use. This is accomplished, moreover, by a structure that is relatively simple and inexpensive, mechanically strong, and which is well suited to modern mass production methods of manufacture, as well as being of neat, compact appearance and of low loss electrical design.

The exact form of the invention here shown is a preferred embodiment of this teaching, and has been chosen as particularly well suited to an explanation of the principles of the invention, but it will be obvious to those skilled in the art that many modifications and departures from the precise form of the invention here shown may be indulged in, and it is accordingly pointed out that the form of the invention here shown is chosen for purposes of illustration rather than in limitation, and that the scope of the inventive concept extends to any modifications or variations thereof within the terms of the appended claims.

Having thus described our invention, what we claim as new and desire to protect by United States Letters Patent is:

1. A hermetically sealed socket comprising, in combination, an airtight sealing member consisting of a relatively thin metal cup having a bottom wall, side walls, and a marginal mounting ange; at least one contact aperture in said bottom wall, with a conductor comprising a metallic pin extending through said aperture and projecting upwardly into said cup; an insulating seal surrounding said pin bonded to the surface of the pin and sealed to the bottom wall of the metal cup, so that the insulating seal supports said pin; together with a socket body comprising -a bottom section and a top section, said bottom section having an aperture in alignment with said contact pin and of greater diameter than said pin so that the pin extends through said aperture of the body but is spaced therefrom at all points, at least one pin aperture in the top section of the socket body in substantial alignment with said aperture in the bottom section thereof, together with an enlarged contact cavity between said apertures, said cavity having oppositely disposed shoulders to retain a metal contact therein; a free floating' metal contact member confined within said cavity and comprising an upper spring sleeve disposed at a contact pin aperture of the top section and a lower spring sleeve in frictional engagement with the upwardly projecting portion of said metallic conductor pin.

2. A hermetically sealed socket comprising, in combination, an airtight sealing member consisting of a relatively thin metal partition having at least one contact aperture therein, with a flange integral with the sealing member surrounding said aperture, a conductor comprising a metallic pin extending through said aperture, and a glass bead surrounding said pin; said bead being bonded to the surface of the pin and sealed to the sealing member respectively; together with a socket body comprising a bottom section and a top section, said bottom section having an aperture in alignment with said contact pin, at least one pin aperture in the top section of the socket body in substantial alignment with an aperture in the bottom section thereof, together with an enlarged contact cavity between said apertures, said cavity having oppositely disposed shoulders to retain a metal contact therein; and a free floating metal contact member conned within said cavity and comprising an upper spring sleeve disposed at a contact pin aperture of the top section and a lower spring portion in frictional engagement with a contact pin extending through the metal partition of the sealing member.

CURT W. KLOSTERMANN. CHARLES J. ADAMS.

References Cited in the le of this patent UNITED STATES PATENTS Ntunber Name Date 2,292,863 Boggs Aug. 11, 1942 2,431,583 Penfold Nov. 25, 1947 2,438,371 Marholz Mar. 23, 1948 2,440,279 Larkins, Jr Apr. 27, 1948 2,444,048 Keller June 29, 1948 2,451,800 Buchanan et al. Oct. 19, 1948 2,472,131 Toth et al June 7, 1949 2,529,502 Kelly et al Nov. 14, 1950 2,603,681 Salisbury July l5, 1952 FOREIGN PATENTS Number Country Date 620,804 Great Britain Mar. 30, 1949 

